This invention relates to apparatus and a method for providing roamer telephone numbers in an international setting.
Roamer service is a cellular mobile wireless service that is provided to customers who leave the area served by their home mobile switching center (MSC), and the immediate geographic area served by that MSC and associated MSCs for serving the geographic area. When a mobile station (MS) registers outside its home area, a remote MSC receives the registration request, and requests that a Visitor Location Register (VLR) create a record for the roaming MS. The VLR queries a Home Location Register (HLR) of the roaming MS in order to notify the HLR of the present location of the MS, and to obtain numerical data such as a call forwarding number and a billing number for the roaming MS. Such data is required for serving the roaming MS from the remote MSC, and is stored in the VLR of the remote MSC.
A problem arises when the home MSC and the remote MSC are in different countries. The telephone numbers that are stored in the HLR and VLR are usually national telephone numbers which do not include, for example, a country code. A problem of the prior art is that the use of the normal telephone numbers stored in the HLR would create ambiguities in the VLR, and make international roamer service awkward or impossible.
The above problem is solved and an advance is made over the teachings of the prior art in accordance with this invention, wherein an HLR in response to receipt of a request for VLR data, tests whether the VLR is in the same country. If not, the HLR prefixes its own country code for numbers stored in the HLR. For call forwarding numbers, such numbers are stored in the HLR, including a country code, if the call forwarding number is outside the country of the HLR. The VLR then stores numbers pertaining to countries outside the VLR""s country to include a country code, but continues to store numbers of the country in which the VLR resides in the format of that country. Advantageously, such an arrangement allows for the storage of international numbers where needed, and national numbers where international numbers are not needed, and facilitates the offering of international roamer service.